Efficient\nTransition Metal Sulfide Electrocatalysts\nPrepared by Laser-Induced Precursor Decomposition

Transition\nmetal sulfides (TMSs) are renowned for their outstanding\ncatalytic performance, earth abundance, and low cost and are widely\nused as electrocatalysts for flexible energy devices. However, their\ncommon synthesis processes usually involve harsh conditions, such\nas high temperature, high vacuum, and time consumption due to the\nhigh formation energy of TMSs, which make it difficult to prepare\nTMSs on temperature-sensitive plastic substrates. In this work, we\nsynthesized TMS catalysts with superior catalytic activity by a fast,\nsimple, and low-temperature laser-induced precursor decomposition\n(LIPD) method. A series of metal–organic complexes (M[BDCA]<sub><i>x</i></sub>), composed of the sulfur-rich decomposable\nbutyldithiocarbamic acid (BDCA) ligands, were chosen as the precursors,\nwhich tend to decompose under the irradiation of a nanosecond-pulsed\nNd:YAG laser (355 nm). It was found that precursors with a high molar\nextinction coefficient, such as Co[BDCA]<sub><i>x</i></sub> and Ni[BDCA]<sub><i>x</i></sub>, were decomposed rapidly\nand completely under this laser to form CoS<sub><i>x</i></sub> and NiS<sub><i>x</i></sub>, respectively. The as-prepared\nCoS<sub><i>x</i></sub> and NiS<sub><i>x</i></sub> showed excellent electrocatalytic properties toward triiodide reduction,\ncomparable with the pyrolyzed Pt. Using LIPD-prepared CoS<sub><i>x</i></sub> and NiS<sub><i>x</i></sub> films as counter\nelectrodes, we fabricated dye-sensitized solar cells with a power\nconversion efficiency of ∼8.5%. This LIPD method ensures the\nformation of TMSs near room temperature (<30 °C), which is\nfeasible to prepare TMS films on the temperature-sensitive plastic\nsubstrates, facilitating their applications in portable electrochemical\nenergy devices.